Paper treatment



atented Mar. 14, 1944 PAPER TREATMENT Harold s. Mitchell, Chicago, nu, assignor to industrial Patents Corporation, Chicago, 111., a corporation of Delaware No Drawing. Application January 20, 1939, Serial No. 253,597

4 Claims. (Cl. 99-171) This invention relates to the treatment of paper prepared for use in wrapping fats and oils or products containing fats and oils.

One of the objects of this invention is to provide a method for treating paper stock used in packaging bakery products, such as cookies or biscuits containing shortening.

Another object of the invention is to provide a treated paper suitable for packaging bakery products.

Other objects of the invention will be apparent from the description and claims which follow.

It is customary to package crackers, cookies and similar bakery products, which must be held for a considerable length of time between packaging and consumption, in cardboard boxes. Such products contain shortening, some of which soaks into the cardboard. Due to the accelerating action of certain ingredients of the cardboard, the fats become rancid and produce an unsavory odor at the time the package is opened. The presence of the rancid fat in the cardboard may or may not adversely affect the product packed in the carton, but in any event the odor is ofiensive and in the case of delicately flavored product may cause deterioration of the product itself. It appears that the onset of rancidity of the fat which soaks into the cardboard is due in part to the increased surface exposure but is most noticeable in the case of cardboards which contain substances such as metals, sulphites, and other materials that tend to catalyze the development of rancldity. The presence of such catalyzers causes rancidity to develop almost immediately after the paper comes in contact. with the baked products from which fat can be absorbed by the cardboard. l

The present invention involves treatment of the cardboard with phosphoric acid.

In one test identical pieces of cardboard of the type employed in packaging bakery products were soaked with alcoholic HzPO; solutions of the strengths indicated in the table which follows. The pieces were allowed to soak up 5 grams of the solution and were then dried in an oven. The impregnated cardboards along with a control were then impregnated with 2 grams of hydrogenated vegetable shortening. The boards conthe hydrogenated vegetable shortening were then cut into strips and placed in 8 ounce jars which were incubated at F. until the shortening was rancid as indicated by organo leptic tests. The following table gives the times at which the rancid odors were detected.

Days to become very rancid 5 Control 0.25% H2PO4 15 0.50% HZPOA 20 1.0% H2PO4 27 Specially manufactured cardboards are prepared in commercial practice for cracker boxes in which parafiln or silicate coatings are used for moisture proofing. Treatment of such coatings with phosphoric acid inhibits the development of rancidity. The phosphoric acid may be added to taining phosphoric acid which will inhibit ran-,

cidity of the fats and oils absorbed by the wrapping material.

2. The method of inhibiting rancidity of fats and oils absorbed by paper wrappers from products in proximity thereto which comprises wrapping such products in phoric acid.

3. The method of packaging which comprises enveloping products containingjfats and oils capable of penetrating the wrapper in a paper wrapping material containing phosphoric acid.

4. The method of packaging food products containing fatty substances normally tending to deteriorate on standing, which comprises packing paper containing phossaid product in a paper container having incorporated therein phosphoric acid in sufficient amount to substantially retard such deterioration.

HAROLD S. MITCHELL. 

